1. Field of the Invention
This invention resides in the area of apparatuses and methods used for the determination of melting points of materials and more particularly relates to an apparatus and method which determine the melting point of a material by changes in reflective properties of the material under different temperatures and pressures.
2. Description of the Prior Art
Many methods are used to determine melting points for materials. The simplest are types where observers note temperatures at which materials, upon heating, become transparent. Such methods first involve immersing the particle of material whose melting point is to be determined in a non-solvent which is heated at a known rate. As the heat from the medium is transferred into the particle, at the point where the temperature of the medium is equal to the melting point of the particle, the particle changes its optical transmissivity and also may change its physical shape. Another method of measuring the melting point of a material utilizes scanning calorimetry techniques or temperature gradient bars where a physical determination of the melting point at which a material will stick to a heat bar is made.
A problem with many of the prior art melting point determination apparatuses is that they lack absolute accuracy in that they require the judgment of an observer as to when a reaction has taken place, and this judgment can vary from observer to observer. Further, many materials can be amorphous in nature and exhibit a range of melting points which many prior art devices do not detect. It has been appreciated in the prior art regarding melting point apparatuses that a substance may change its light transmissibility at its melting point and apparatuses to measure the change in light transmission when a material passes from a solid continuous phase to a liquid continuous phase is disclosed in U.S. Pat. No. 2,669,863 by Shapiro. Further the use of different pressures when determining melting point is appreciated in U.S. Pat. No. 4,484,822 to Hancock. Also in the prior art the process of dielectronomy is known where test samples arc measured by their transmissiveness to microwaves under various conditions including heating.